A new Ophiostoma species from loblolly pine roots in the southeastern United States

During the course of a survey of fungi in loblolly pine (Pinus taeda) roots in Georgia, USA, a species of Ophiostoma morphologically similar to O. pluriannulatum, was isolated. Morphological characteristics and DNA sequence comparisons were used to identify the fungus. The isolates produced perithecia with unusually long necks similar to those of O. pluriannulatum but they had few or no annuli. DNA sequences for the ribosomal internal transcribed spacer regions 1 and 2 were identical to those of O. pluriannulatum. Sequence data of the β-tubulin gene region revealed the absence of intron 4 and presence of intron 5, distinguishing the isolates from O. pluriannulatum, which has intron 4 but not intron 5. Phylogenetic analyses of the β-tubulin sequences showed that the isolates from loblolly pine roots grouped together in a lineage distinct from O. multiannulatum and O. subannulatum, both of which lack intron 4 and have intron 5. The fungus is consequently described as O. sparsiannulatum sp. nov., a novel taxon in the O. pluriannulatum complex.